Yes—old Yashica/Contax bayonet lenses can often be used on modern digital cameras with a Contax/Yashica (C/Y) mount adapter. Adapters are available for several major camera mounts, including Canon EOS bodies.

The main limitation is that these adapters usually provide only the physical mount connection. In practice, that means you’ll typically use the lens in full manual mode: manual focus and manual aperture control, with no electronic communication between lens and camera.

Some adapters include a focus-confirmation chip, which can help with focusing by working with certain camera autofocus confirmation features, but the lens itself still won’t become autofocus.

So the short answer is: yes, you can likely reuse the lenses, but not as native lenses. You’ll need a compatible adapter, and you should expect a manual shooting workflow.